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DHCP reservations and Dynamic DNS Updates

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  • Is n't a reservation also a lease given, but at a non-negotiable address?  So, my point is, shouldn't DHCP also update DNS for reservations when the indicated client appears?


    Chris.

    Can you please elaborate more on this, what are you trying to accomplish?

    Regards, Ravikumar P

    יום שני 11 יוני 2012 15:03
  • Hi Ravikumar,

    I want DHCP to update DNS to reflect the state of the attached device.  Device appears, add a record to DNS; device disappears, remove the record from DNS.  The reservation should obviate the address negotiation, but nothing else; meaning DHCP should update DNS, and provide all the other settings like gateway.


    Thanks for the help,

    Chris.

    יום שני 11 יוני 2012 18:35
  • From what you're saying, I think the best way to handle it is to use DHCP Credentials and force DHCP to update all leases for forward and reverse entries. More info on how to do this here:

    This link covers the following:
    DHCP Service Configuration, Dynamic DNS Updates, Scavenging, Static Entries, Timestamps, DnsUpdateProxy Group, DHCP Credentials, prevent duplicate DNS records, DHCP has a "pen" icon, and more...
    Published by Ace Fekay, MCT, MVP DS on Aug 20, 2009 at 10:36 AM  3758  2 
    http://msmvps.com/blogs/acefekay/archive/2009/08/20/dhcp-dynamic-dns-updates-scavenging-static-entries-amp-timestamps-and-the-dnsproxyupdate-group.aspx  


    Ace Fekay
    MVP, MCT, MCITP EA, MCTS Windows 2008/R2, Exchange 2007 & Exchange 2010, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
    Microsoft Certified Trainer
    Microsoft MVP - Directory Services
    Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php

    This post is provided AS-IS with no warranties or guarantees and confers no rights.

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    יום שלישי 12 יוני 2012 00:04
  • Hi Ace,

    I am configured as you suggest.  I am also using "Name Protection" which forces my update options as follows:

    ... which I think is just what I want.  So, the question remains, why DHCP does not appear to perform dynamic DNS updates in the event of Reservations, which as far as I know simply means we can dispense with the address negotiation; everything else is still delivered to the client.


    Thanks for the help,

    Chris.

    יום שלישי 12 יוני 2012 00:20
  • Hi,

    Are there all reservations not update DNS records or only specific devices? You can test with a normal Windows client with reservation assigned. Meanwhile, please check the reservation setting. Make sure that the DNS dynamic update was enabled. Reservation Properties -> DNS

    In addition, please try to run the command ipconfig /release and ipconfig /renew to update the DNS record. If it’s a device, please try to unplug the cable and plug again, to see if the issue still persists. Also, check the following KB article. Hope it helps.

    A client computer that held a DHCP reservation is not resolvable by using DNS after you delete the reservation on a DHCP server that is running Windows Server 2003

    http://support.microsoft.com/kb/940722

    Best Regards,

    Aiden


    Aiden Cao

    TechNet Community Support

    יום שלישי 12 יוני 2012 02:14
  • Ahh, it's 2008 R2. My bad for not asking and assuming otherwise.

    .

    When you run the BPA, what do you find?

    Best Practices Analyzer
    http://technet.microsoft.com/en-us/library/dd759260.aspx

    .

    The link Aiden provided is for 2003, but it applies to 2008/2008 R2 as well.


    Ace Fekay
    MVP, MCT, MCITP EA, MCTS Windows 2008/R2, Exchange 2007 & Exchange 2010, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
    Microsoft Certified Trainer
    Microsoft MVP - Directory Services
    Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php

    This post is provided AS-IS with no warranties or guarantees and confers no rights.

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    יום שלישי 12 יוני 2012 02:21
  • In addition thinking this through after I posted, can we see an unedited ipconfig /all from one of the machines with a reservation, please?

    What we're looking for:

    • Primary DNS Suffix matches the zone name in DNS
    • Connection Specific Suffix (if using Option 015) matches the zone name in DNS
    • Only the internal DNS servers are used (Option 006)

    .

    And curious if Aiden's suggestions for a release and renew takes care of it, or a restart?


    Ace Fekay
    MVP, MCT, MCITP EA, MCTS Windows 2008/R2, Exchange 2007 & Exchange 2010, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
    Microsoft Certified Trainer
    Microsoft MVP - Directory Services
    Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php

    This post is provided AS-IS with no warranties or guarantees and confers no rights.

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    יום שלישי 12 יוני 2012 02:33
  • Hi Aiden,

    When Name Protection is enabled, the dialog you posted is almost completely disabled, which is why I showed the dialog I did.

    Hi Ace,

    DHCP doesn't have a BPA on the Server Manager.  DNS BPA complains about "The network adapter Local Area Connection does not list the loopback IP address as a DNS server, or it is configured as the first entry." which I have tried in vain to clear with zero success.  I suspect this comes from IPv6, which I am not using.  What do we seek?

    Ace and Aiden,

    ipconfig/... is only valid on Microsoft systems, and DNS has a broader scope than Microsoft systems.  In particular appliances, NAS, Router/Gateway, Linux, ... DHCP should update DNS with no more provocation than disconnecting and reconnecting the cable.

    Thanks for the help,

    Chris.



    • נערך על-ידי cjm51213 יום שלישי 12 יוני 2012 18:28 Correct an error on my part
    יום שלישי 12 יוני 2012 17:56
  • Chris,

    I believe Aiden assumed it was Windows 2003, since you didn't previously post the OS version. I realized it was 2003 R2 after you posted the screenshot.

    .

    The BPA will look at anything installed on the machine, for the most part. The BPA DNS loopback message is looking for the loopback as an entry in NIC's DNS settings. YOu can either ignore the loopback message, or at least make sure either the loopback or its own IP is second in the list, and another DC/DNS is the first.

    .

    True that you can disconnect/reconnect, but it may not re-register if the machine is up and hasn't been restarted before the 24 hour re-registration period is up for workstaions and member servers. FYI, DCs are every 60 minutes. That's why we were curious if a /registerdns would work for a Windows machine that has a reservation.

    .

    Are there more than one DHCP server?

    .

    Based on the screenshot Aiden provided, do you see the same thing for your reservations, that is looking at the properties of a reserved IP, "Name Protection is disabled on the scope that contains this reservation?" If so, that could be causing it. If so, let's disable Name Protection, and configure Credentials, and test that out.

    .


    Ace Fekay
    MVP, MCT, MCITP EA, MCTS Windows 2008/R2, Exchange 2007 & Exchange 2010, Exchange 2010 EA, MCSE & MCSA 2003/2000, MCSA Messaging 2003
    Microsoft Certified Trainer
    Microsoft MVP - Directory Services
    Complete List of Technical Blogs: http://www.delawarecountycomputerconsulting.com/technicalblogs.php

    This post is provided AS-IS with no warranties or guarantees and confers no rights.

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    יום שלישי 12 יוני 2012 20:46